Five questions facing Arsene Wenger on Arsenal's preseason tour

Arsenal are already halfway through their preseason tour and some pieces have started coming together for manager Arsene Wenger. New signings Alexandre Lacazette and Sead Kolasinac have both slotted in well, players are adapting to new roles and long-term injury victims like Per Mertesacker and Danny Welbeck are looking fully fit.

But there are still some question marks for Wenger to sort out as the Gunners continue their trip with two games in China this week -- against Bayern Munich in Shanghai on Wednesday and Chelsea in Beijing on Saturday. Here's a look at five questions Wenger has to solve.

Can Alexandre Lacazette and Olivier Giroud play together?

While Lacazette is expected to take the central striker role from Giroud, Wenger has made a point of playing them together so far and started both in Saturday's win against Western Sydney Wanderers.

Perhaps Wenger sees Lacazette playing behind Giroud -- especially if Alexis Sanchez does end up leaving the club -- but the WSW game raised some questions about whether the players themselves can do it.

Giroud, in particular, was singled out by some fans who felt he passed up the opportunity to feed Lacazette the ball and then ignored his France teammate after scoring the opening goal. That may be a mini-controversy over nothing -- although one would understand if Giroud wasn't overly excited about having Lacazette in the team -- but if he stays at Arsenal this summer, then his best chance of getting regular playing time may be to show that he and Lacazette can form a deadly duo.

What is Theo Walcott's role, exactly?

Walcott was one of the big losers when Wenger switched systems to a three-man defence late last season. With the width provided by the wing-backs and a narrower forward line, his usual position on the right wing was eliminated and left the pacey forward without a clear place in the team -- as evidenced by him starting just one game in the new formation.

Heading into the new season, Walcott's purpose is still unclear -- even though he says he's held talks with Wenger about his role. Walcott played in one of the two attacking midfield positions against Sydney FC, but those will be occupied by Mesut Ozil and Sanchez (if he stays), or possibly Thomas Lemar if Arsenal can pull off a deal for the Monaco star.

Walcott certainly won't displace Lacazette up front, while the likes of Danny Welbeck, Alex Oxlade-Chamberlain and Alex Iwobi also provide competition. Things may change if Wenger reverts to his normal formation, but right now it's hard to see Walcott being more than a bit-part player next season. Which raises the question: Should Arsenal entertain offers for their longest-serving star?

What to do with all the centre-backs?

With Calum Chambers returning from a loan spell at Middlesbrough, Arsenal will have six senior centre-backs at their disposal. And that's not counting Nacho Monreal and Sead Kolasinac, who can both be deployed in a back-three if needed.

Even when playing three at the back, that's probably too many to fit into the squad. So Wenger might face a tough decision at the end of the summer: Trim his numbers by sending either Chambers or promising youngster Rob Holding out on loan, or keep everyone at home and risk alienating those who are left out of the team.

The end of last season showed just how quickly a crisis can emerge, as Arsenal were without Laurent Koscielny, Shkodran Mustafi and Gabriel Paulista for the FA Cup final, so there is safety in numbers. But Holding and Chambers need regular playing time to continue their development and it's unlikely they can both get it at Arsenal.

Which youngsters are ready for the big time?

Preseason is a great time for Arsenal's academy players as a handful usually get regular minutes during the friendlies. In the past, some, like Hector Bellerin and Alex Iwobi, have used that chance to stake a claim for a permanent spot in the first team, and several are knocking on the door once again.

Midfielder Reiss Nelson impressed in Australia and the 17-year-old will look to back that up with another strong performance against tougher opposition in China. Others like striker Eddie Nketiah and left-back Cohen Bramall will also try to force themselves into Wenger's plans -- or at least put themselves in the shop window for an attractive loan move.

Can Emiliano Martinez be Petr Cech's backup?

Of all the players who are on this tour, David Ospina is perhaps the most likely to be sold this summer. The goalkeeper continues to be linked with a move to Fenerbahce and doesn't want to spend another year as Petr Cech's backup. With Wojciech Szczesny in talks over a move to Juventus, it means Wenger must decide whether Emiliano Martinez is good enough to be his No. 2 next season.

The Argentine played 45 minutes in each of the two games in Australia and his audition is likely to continue in China. These games may be friendlies, but for Martinez they could have a major impact on his career.